Known as an color image forming method is one, employing a so-called intermediate transfer system, in which a latent image formed on an electrostatic latent image bearing body is developed employing toner; instead of transferring the resulting toner image directly onto an image forming support, said toner image is temporarily transferred onto an intermediate transfer body; thereafter, the toner image is re-transferred onto an image forming support; and the toner image, which is transfer formed onto the image forming support, is then fixed.
In the intermediate transfer system, each toner image formed on the latent image bearing body is transferred onto the intermediate transfer body a plurality of times, for example, four times. By such procedure, each of several color toner layers is laminated (each color is superimposed). In such an operation, occasionally as each color toner layer is transferred onto the intermediate transfer body, non-uniform transfer occurs.
On the other hand, widely employed, as a device to fix toner images formed on the image forming support, is a heating roller fixing system utilized in a fixing apparatus provided with a heating roller and a pressure roller. In this system, since toner comes into contact with the surface of the heating roller, toner is subjected to electrostatic repulsive force so as to be occasionally repelled.